Apparatus for dough preparation



Nov. 23, 1937. E. J. LAUTERBUR APPARATUS FOR DOUGH PREPARATION Filed April 9, 1954 4 Sheets-Sheet 1 w mw V INVENTOR.

EnwARn J. LAUTERBUR ATTORNEYS.

Nov. 23, 1937.. E. J. LAUTERBUR APPARATUS FOR DOUGH PREPARATION Filed April 9, 1934 4 Sheets-Sheet 2 PIIIIXIU INVENTORT V M ATTORNEYS.

u x mw EuwARnJ. LAUTERBUR.

Nov. 23, 11937. E. J. LAUTERBUR APPARATUS FOR DOUGH PREPARATION 1934 4 Sheets-Sheet 3 Filed April 9 lTJVF- JTOR. EDWARD J. LAUTER BUR.

ATTORNEYS,

Nov. 23, 1937. E. J. LAUTERBUR APPARATUS FOR DOUGH PREPARATION Filed April 9, 19:54

4 Sheets-Sheet 4 1N VEN TOR.

EDWARD ILAUTERBUR- ATTORNEY5- Patented Nov. 23, 1937 PATENT OFFICE APPARATUS FOR DOUGH PREPARATION Edward J. Lauterbur, Sidney, Ohio, assignor to Peerless Bread Machinery Corporation, Sidney, Ohio, a corporation of Ohio Application April 9, 1934, Serial No. 719,885

Claims.

and automatic control of supply of leavening agent to the contents of the mixing apparatus,

and a more rapid and thorough distribution of' this supply.

A further object is to provide for subjecting the contents of the mixing apparatus to the action of light rays of a desired character, during the mixing operation.

A further object is to provide efliacient means for cooling or controlling the temperature of the mixing apparatus and the contents thereof during the mixing operation; and preferably, to

provide for such cooling in a bowl which is tiltable for damping the contents, with suitable connecticns from a stationed refrigerating apparatus to the tiltable bowl.

A further object is to provide a tiltable mixing bowl with automatic control of the degree of tilting and return from tilted position; and to provide for either power or manual tilting, either one as desired, without hindrance by the means provided for the other kind of tilting.

A further object is to provide for powerful driving of agitating means to effect the mixing, with the power so applied as to impose a minimum of strain on the power transmission from the motive means to the agitator member.

A further object is to provide for very convenient control of the speed of the agitating mechanism; and preferably for automatic control of the duration of operation thereof. A further object is to provide, in conjunction with the duration control, for a manual control of th agitator operation.

A further object is to provide, in conjunction with a bowl that is tiltable and an agitator controlled as above described, means for insuring against simultaneous tilting of the bowl and agitator operation; yet allowing for operation of the agitator under manual control while the bowl is tilted.

A further object is to supply the water ingredient to the contents of the bowl at a controlled temperature and in controlled quantity, by very readily observed and manually operated means.

A further object of my invention is to provide for any two or more of the above objects, 5 by an assembly and arrangement of devices for performing the several functions, in a compact unit, with the several devices located most advantageously for proper action, of themselves and in coaction with the other device or devices, and for ready access for the manual control and supervision of their operation.

Other objects, additional to or incident to the above mentioned objects, will occur in the course of the following description, illustrated by the accompanying drawings, in which- Figure 1 is a side elevation of an entireunit embodying my invention, parts being broken away to reveal the sifting device in section.

Figure 2 is an enlarged partial side elevation 20 corresponding to that of Figure l, with the bowl partly in section to reveal the agitating and brak ng means in elevation, and with the base and the lower part of the right hand column broken away to reveal the blower and its air 25 cooling device in section, and the refrigeration apparatus in elevation.

Figure 3 is a verticalcross section on the line 3-3 of Fig. 1.

Figure 4 is a partial similar section showing a modification of the bowl bottom.

Figure 5 is a diagram of the electrical controlling devices and their connections.

As I prefer to construct my improved dough preparing unit, a base I supports the left hand column 2 with a top head or hood 3, and the right hand column 4 with a top head or hood 5. In the space between these columns and spaced up from the base I is the mixing bowl 6 containing the agitator I which is fixed on the shaft 8 having bearings 9 in the side walls of the bowl. Each bearing has an extension. Ill, and these extensions have trunnion bearings H in the adjacent walls of the columns 2 and 4, respectively, pivoting the bowl 6 for tilting forwardly. The agitator shaft 8 extends through its bearings 9 and is continuous withthe shafts of the speed reducing gearing units 8a connecting with the motors l2, which are located in thehoods 3 and 5, respectively. The agitator I is thus connected to both motors I2, so that each motor l2 supplies its portion of the power close to the agitator for rotating it; avoiding undue torsional strain on the shaft, such as would be imposed if one motor of the required power were stationed at one side only of the apparatus.

The agitator 1 is made up of spiders Ia fixed to the shaft 8 adjacent the respective side walls of the bowl 6, and bars lb each with opposite ends fixed in arms of the spiders; these bars lb being bent into bowed shape transversely of the bowl as well as being pitched at inclinations to the axis of agitator rotation. This construction affords an especially effective agitating and distributing action on the contents; but it does not require extended consideration herein, being fully disclosed and claimed in Patent No. 1,726,033, issued August 27th, 1929.

I prefer also to provide the apparatus with a stationary cover l3 for the bowl, supported on arms I4 upstanding from the tops of the column hoods 3 and 5, respectively. This is a construction fully set forth and claimed in my Patent No. 2,025,541 issued December 24, 1935. The cover 5 curves down at the rear so that its rear rim I5 is abutted on its forward side by the rim l6 of the rear wall of the bowl 6, allowing the bowl to swing forward therefrom, yet to tightly engage this rim IS with the cover rim l5, as well as its side rim Ilia with the side portions of the cover l3, when the bowl is tilted upward into position for the mixing operation. The front part of the cover I3 is straight, the side rims Ilia of the bowl conforming thereto; and a lid ll, preferably in the form of a frame with a glass or other transparent panel I la, is connected to the front edge of the cover l3 by a hinge l8. The front parts of the side rims of the bowl are slanted downwardly and forwardly to the top rim of the front wallof the bowl; and this lid I'I rests snugly on these rims when closed. The lid has forks I 9 that straddle the bowl when this lid is closed; and at opposite sides, adjacent to the hinge 18, are latches 20 on the cover l3 and lugs 2| on the lid H, which mutually retentively engage automatically when the lid I1 is raised to a certain height. The adjacent side walls of the bowl 6 have pins 22 which engage the respective forks l9, raising the lid until it is held by the latches 20, when the bowl 6 is tilted forwardly; and at this position, the lid has swung the longer rear members of its forks l9 into the paths of these pins 22, so that they release the lid from its latches, to return into closed position again under control of the fork and pin engagement, when the bowl is returned from its tilted position.

In a rear lower type of the interior of the bowl 6 is a brake 23, preferably of the roller type, diverting the bowl contents from the bowl wall with a minimum of friction, as set forth in the patent above mentioned; and also, after the principle of that patent, there is an upper rear brake 24, which however, is mounted to swing, as set forth and claimed in my patent above mentioned. This brake is in the form of a transverse bar, the ends of which are held in the lower ends of arms 25 near respective sides of the bowl interior; the upper ends of these arms 25 being pivotally connected at 26 with lugs on the under side of the bowl cover l3, which also supports latches 21 with which ribs 28 on the sides of the respective arms 24 retentively engage when the arms, with the brake 24, are swung upward by engagement of the rear rim l6 of the bowl with the arms, as the bowl is tilted forwardly. These latches 27 engage automatically and hold the arms and brake up for return of the rear rim l6 therepast; whereupon the rear rim it engages lugs 29 on the arms 25, pulling the arms down from the latches 21, to drop with the brake 24, to operative position again. This position is determined by adjustable stop screws 30 threaded through the cover I3 and engaged by the rear sides of the lugs 29.

Just forwardly from the brake support just described, the cover I 3 has an upwardly projected portion or hump 3|, forming an enclosure, within which, preferably near opposite ends thereof, are mounted lamps 32, which will be understood to be of any special character, such as ultra-violet-ray lamps, for affording a desired action on the mixer contents; as for instance, to augment their vitamin content. In the rear lower part of this hump 3| is the water distributing means, preferably in the form of a tube 33 of rather large diameter, extending transversely of the bowl and having perforations 33a at desired locations in its bottom wall.

Just forwardly from this hump 3| the cyclone separator casing 34 has its downwardly tapering lower part extended through and fixed to the bowl cover l3; this casing being open at its bottom for discharge into the bowl 6. Above this tapered part the casing 34 is cylindrical; and it is open at its top, with the pervious bag 35 secured over the open top. A dome 36 encloses this bag 35, being spaced therefrom throughout the sides and top of the bag, and being connected to the top rim of the cyclone separator casing in an air tight manner.

In front of the cyclone separator casing is the yeast pct 31, set into and fixed in the cover I 3, with its bottom below the cover and having perforations 37a for discharge into the bowl 6.

The front and rear bowl walls, substantially throughout their areas, and the curved bottom of the bowl, are covered by a jacket 38 having the inside of its outer wall lined with suitable insulation 38a, such as cork, for resisting the passage of heat into the jacket. Hugging closely to the bowl walls and bottom, inside this jacket 38, are the refrigerating or cooling coils 33, being, as here shown, in the form of pipes extending transversely of the bowl and connected at their ends by return bends, forming a sinuated system of conductors for expanding heat absorbing medium, as is well known in the art of refrigeration.

Along each edge of the curved bottom of the bowl 6, exteriorly thereof, segmental racks 40, concentric with the tilting of the bowl on its trunnions ID, are fixed to the bowl. Meshing with the respective racks 40 are pinions 4| fixed on a shaft 42 extending transversely of the bowl at the rear lower part thereof and journaled in the inner walls of the respective columns 2 and 4. Near its bearing in the right hand column 4, this shaft 42 has fixed on it a pinion 43 meshing with a gear sector 44 which has fixed concentrically to it two cams 45 and 45a, all rotatable on a stud in the adjacent wall of the column 4. The shaft 42 extends past its bean'ng into the left hand column 2, where it has fixed on it the worm gear 46, meshing with a worm 41 fixed on a shaft 48 with a spur gear 49; this shaft 48 being journaled in the column walls. A handwheel 50 is fixed on the part of a shaft 5| extending out through the front wall of the column 2, in which the shaft is journaled; and on the part of this shaft 5| inside the column is fixed a pinion 52 meshing with the gear 49. The worm shaft 48 also has fixed on it a sprocket wheel 53, connected by a chain 54 with a sprocket pinion 55 fixed on the shaft of a motor 58 mounted in the lower part of the column 2.

The shape of cams 45, 45a is shown in Fig. 3, where are shown also the switches 51 and 58 operated thereby to automatically limit the forward or dumping tilting and the rearward or return tilting, respectively, of the bowl 6. The forward limit switch 51 is connected by wires 59 and 59a, and the rearward limit switch 58 is connected by wires 68 and 69a, to control devices hereinafter to be described.

On the base I, near the right hand column 4 is the refrigerating compressor 6|, having a fly wheel 62; and a belt 63 connects this fly wheel to a motor 64 at the left, by passage around the small pulley 65 thereof. To the rear of the motor 64 is the condenser 66, as here shown, made up of a sinuated system of pipes with one end 66a leading from the cylinder of the compressor 6| and theother end 66b leading into the top of the receiver 61, in which the refrigerating mediumis received in highly condensed or liquid form. The outlet of this receiver 61, at its bottom, has an expansion control valve 68, understood to be of any suitable type as well known in .the refrigerating art. The refrigerating or cooling coils 39 of the bowl jacket 38 are served by the inlet pipe 69, leading from this expansion control valve 68 to the left and upward; and by the return pipe 10 leading downward at the right of the bowl, to the intake of the compressor 6|.

For connection of these pipes 69 and 10 to the tiltable bowl 6, systems of swivel pipe connections are provided, each comprising a swivel joint 1| connecting the pipe 69 or 10 to a pipe section 12, a second swivel joint 13 connecting this section 12 to a second section 14, and a third swivel joint 15 connecting this second section 14 to the inlet end or the outlet end, as the case may be, of the system of refrigerating coils 39 in the jacket 38. The condensed or liquid medium from the receiver 61, expanding in the coils 39, as is well known in the art, absorbs heat from the bowl walls and contents, whether that normal to them under influence of atmospheric friction of the contents, either internally or with the bowl, agitator and brake structures, in the course of mixing. This temperature may be controlled by control of the rate of operation of the compressor 6|, or its degree of compression, and by the expansion control valve 68, so that the bowl contents may be maintained at any desired temperature throughout the mixing.

This control, however, would be affected by the temperature of the water introduced into the mixer as an ingredient of the contents, as well, to a less extent, by the temperature of the flour or like ingredient. Also, control of the temperature of the flour or the like is a control of its humidity, and generally affects its consistency as discharged into the bowl.

To control the temperature of the water, the water cooling tank 16 is mounted in the base I near the left hand column, with a jacket 160. provided with cooling coils 11 around the tank. A pipe 18 has a T connection with the bowl coil inlet pipe 69 and with the inlet to the cooling tank coils 11, at the bottom thereof, and has a valve 18a interposed in it; and from the outlet of these coils, at the top thereof, a pipe I9 leads to a cross connection 19am the bowl coil return pipe 18. Expanding cooling medium thus is shunted from the bowl coil system into the tank coils 11, in proportion determined by the opening of the valve 18a. Leading into the top of the cooling tank 16 is the water inlet pipe 88, understood to lead from any suitable source of water supply, preferably a water purifying apparatus, known in the art, and therefore not illustrated. From the bottom of this cooling tank 16 leads the pipe 8| to the right and upward in the right hand column 4 and its hood 5, entering, in the hood 5, the intake side of the water supply pump 82. From the discharge side of this pump a pipe 83 leads upward and to the left into the adjacent end of the distributing pipe or head 33 that discharges the water into the bowl as before described.

A branch pipe 84 leads from a valve 85, interposed in the pipe 83, to the yeast pct 31, which it enters at a tangent to the cylindrical cross section of the pot; so that water, in quantity controlled by the valve 85, thus entering the pot will agitate the yeast or other leavening ingre dient with a swirling motion, insuring its thorough dissemination as it is discharged into the bowl 6 through the perforations 31a in the bottom of the yeast pot, as previously described.

The water supply pump 82 is driven by the motor 96; both the pump and motor being understood to be mounted on a wall of the hood 5.

To control the temperature of the flour or the like, an air cooling casing 81 is mounted on the base I in the right hand column 4, and contains a system of cooling coils 88. The lower end of these coils 88 is entered by a pipe 89 having a T connection with the bowl coil inlet pipe 69, and having interposed in it a valve 89a; this pipe extending along inside the base I. The upper end of these coils 88 is connected by a pipe 90 with the T connection 19a, before mentioned, in the bowl coil return pipe 10. Thus, expanding cooling medium is shunted from the bowl coll system into the air cooling coils 88 in proportion determined by the opening of the valve 89a.

The air cooling casing 81 has the outlet 9| into the central intake of the blower 92, mounted on the base I at the right of the casing 81. Into the top of this air cooling casing 81 leads the pipe or conduit 93 from the dome 36 of the cyclone separator device on the bowl cover I3. From the peripheral outlet of the blower 92 the pipe or conduit 94 leads to the casing 34 of the cyclone separator device, entering this casing tangentially so that the incoming air takes a swirling or cyclone motion whereby it throws loose the flour or the like which it carries; the flour or like material to drop into the bowl 6, and the air, freed of the material, to escape through'the pervious bag 35 into the dome 36, from which it is drawn back through conduit 93 into the air cooling casing 81. The supply conduit 94 leads up along the back of the apparatus; and the return pipe 93 leads down through the righthandcolumn hood 5 near the front of the apparatus, as best seen in Fig. 3.

The flour or like pulverulent material is introduced into the blower. discharge pipe 94 by means of a Venturi device 95 operating below a funnel shaped inlet 96 in the top wall of the horizontal part of the pipe 94 where it leads from the, blower. The sifter casing 91, of cylindrical shape on a horizontal axis, has in its bottom the sifting outlet comprising a screen 910, as best seen in Fig. 1. Leading from the left end of this casing 91, next to the screened bottom thereof, is the tailings spout 98, for discharge of coarse particles or tailings which are not passedthrough the screen 91a; and a removable receptacle or drawer 98a rests on the base I under this spout 98, for recovery of the tailings. The sifter casing 91 has, leading from its bottom, under the sifter screen 010, the funnel shaped discharge spout 00, which enters but does not make contact with the walls of the funnel shaped inlet 90 of the blowerv discharge conduit 94. This spaced relation of these parts is provided so that the sifter casing is free to move with the weighing supply bin, as will presently be described; and the opening thus left does not interfere with the impelling action of the blower on the pulverulent material, since the action of the venturi 95 is slightly that of drawing air down from the sifter casing and through the space thus left, drawing the material into the conduit 94, whereitis carried with the full force of the blast from the blower 02, to the cyclone separator device. This construction and operation are fully set forth and claimed in my Patent No. 2,003,716, issued June 4, 1935. The blower 92 is driven by a motor I mounted on the right hand side of the blower casing as seen in Fig. 2; this blower being understood to be any suitable one of well known types of centrifugally acting blowers.

The weighing bin casing IOI, at the right of the entire apparatus above described, contains the bin I02 of rectangular box like shape in its top portion, with a bottom narrowing to a substantially semi-cylindrical trough shaped conduit part I03, the left end of which has a connection I04 with the right end of the sifter casing 91, as best seen in Fig. 1. Concentric with the sifter casing and this conduit part, the conveyor shaft I05 has its left end part journaled at I05a in the left end of the sifter casing 91, and its right end part journaled at I05b in the right end wall of the bin I02; thus extending throughout the combined lengths of the sifter casing and the bin conduit part. In the sifter casing this shaft I05 has fixed on it the brush I06 which sweeps the walls of the casing and the sifter screen 91a, to

force the pulverulent material down through the screen 91a into the outlet 09 for conveying action as above described.

In the trough shaped conduit part I03 of the bin I02, the helical conveyor screw I0! is fixed on the shaft I05, together with a helical blending screw I08 of much higher pitch than the conveyor screw, so that it acts between the turns of the less highly pitched conveyor screw to thoroughly blend different kinds of pulverulent material, such as different grades or kinds of flour, in the course of travel of the materialtoward the sifter casing 91 under the forcing action of the conveyor screw I01. The conveyor shaft I05 is rotated by means of a large sprocket wheel I09 fixed thereon where it projects outside its bearing I05b in thebin wall, and a chain IIO connecting this wheel I09 to a small sprocket wheel III on the shaft of the motor I I2. The motor is mounted inside the casing IOI on a wall thereof with the shaft projecting through the wall, to carry the sprocket wheel II I, which with the chain H0 and sprocket wheel I09, is enclosed in a small casing I09a on the outside of the bin wall.

Thecasing IOI and the bin I02 are supported on a frame which comprises a back bar H3 and a front bar 311., and the bin has a back bar Ill. Near respective ends, the back bars H3 and III have pivot bearings II5 between them whereby the bin is mounted to swing up and down in a front-to-rear plane, on the casing frame. -This, as well as the immediately later described construction, is fully disclosed and claimed in my co-pending application, Serial No. 699,206, filed November 22, 1933; so that elaborate disclosure thereof is not necessary; this entire weighing bin apparatus being an element of my present invention only in a broad sense, not concerning its detailed construction. It is sufllcient to explain that the bin I02 has a front bracket 6; that a link II'I suspends the left end of a beam H8 from the front frame bar Ilia; that the bin is suspended by its front bracket IIG from this beam II8 near the link In; and that the opposite end of the beam III! is suspended by a link II9 from the scale beam I20, which is fulcrumed on a post I2I on the front frame bar 3a. The beam I 20 has three sections, on which are poises I22, I22a. and I22b, respectively, and swings up under the weight of the material placed in the bin I02, and by moving the lower poise I22 to the left until the beam swings-down, the weight of the material in the bin is indicated. The upper poises I22a and I22b are moved to the right to indicate the amount desired to be discharged from the bin. A dash pot I23, fixed on the frame of the front bar II3a, has a connection I23a to the beam to the right of its fulcrum I2 I, making the up swing of the beam I20 gradual.

A cut out switch I24 for the conveyor driving motor H2 is also mounted on the frame and is so actuated by the beam I20, as it swings down upon reduction of the weight of material in the bin I02 by discharge therefrom to the sifter and mixing apparatus, that this switch is opened and the motor H2 and the conveyor are stopped. Thus, by the use of the poises I22a and I22b, in conjunction with this control by the switch I24, the apparatus may be set to discharge any predetermined quantity of material. A two-button switch I24a also is provided for manually starting and stopping the motor 2.

0n the front of the hood 3 of the left hand pedestal 2 is mounted a switch with three buttons I25, I25a and I 25b for manual control of tilting of the bowl 6; the first two being for return of the bowl from tilted or dumping position and for tilting or dumping the bowl, respectively, and the third being for stopping the tilting or return at any desired stage. Just below this switch is a switch with three buttons I25, mm and I25b, for causing high speed, low speed and stoppage, respectively, of the agitator I. Below these switches are control clocks I21 and I2'Ia. Clock I21 keeps the motors I2 running at low speed for duration of time set, and then shifts them to high speed. Clock I2Ia keeps motors at high speed for its set duration and then stops motors I2. Above these clocks is an inching switch I28 with two buttons, for starting and stopping the agitator I; being a manual control for moving the agitator independently of the clock control. Up to the right of these devices is a rheostat I29 for control of current to the lamps 32, to vary their intensity.

On the front of the upper part of the right hand column hood 5 is a revolution counter I30, by which may be observed the number of revolutions made by the water supply pump 82, which, the pump having a known capacity per revolution, enables the operator to note the completion of supply of any desired quantity of water to the bowl 6. Just below this counter I30 is a two button switch I3I for starting and stopping the motor 86 of this pump 82, under the guidance of the counter I30 as just described. On the front of the left hand column hood 3, down to the left of the devices previously described as being thereon, are the two-button switch for starting and stopping the motor I of the blower 92, and the two-button switch I33 for starting and stopping the motor 64 of the compressor 6| the latter switch I33 thus affording manual control of the refrigeration of the bowl 6,0! the water supply and of the air-actuated supply of flour or the like.

In the front of the lower part of the left hand column 2, is the panel I34 which carries the electrical control devices associated with the various outside devices just above described; and which when swung open, affords access to them for adjustment or repairs. The devices on this panel I34 are not illustrated except in the diagram, Fig. 5, wherein all of them are shown, with their connections to the various outside devices and the apparatus they control, as well as the source of current supply. This is shown as a three-wire system; but it will be understood that it may be adapted to a two-wire system.

In this diagram, at I24 are shown the controller for the sifter and conveyor motor H2, and its relation to thecut out switch I24 and starting switch I24a and motor H2; at I25 are shown the reversible bowl-tilt control, its relation to the switch buttons I25, I25a and I25b and the cam actuated switches 51 and 58 and the motor 56; at I26 are shown the two-speed agitator control and its relation to the switch buttons I26, I26a and I26b and the motors I2;, at I26" are shown the stop switch in its relation to the switch button I 26b and the motors I2 at I21 are shown the pole-changing switch for changing from low speed clock I21 to high speed clock speed I21a, accordingly as the agitator is to be operated at one or the other speed, and its relation to the clocks; and at I3I', I32 and I33 are shown the controls for the water pump motor 86, the flour-conveying blower motor I00 and the refrigerating compressor motor 64, and their relation to the two-button switches I 3I, I32 and I 33, respectively.

Provision also is made for preventing operation of the agitator I when the bowl 6 is tilted for dumping; and also for preventing dumping while the agitator is running. The agitator cut out is shown at I35 in the diagram; the dump cut out at I36. These are interlocked at I31, and I38 is the interlock out out, which is closed with the bowl tilted and open with the bowl in operating position; acting as a jumper around the electric interlock I31 to permit inching in both high and low speed. Contacting the inching switch I20 permits the operator to hold in the low or high speed push button, and then both the motors I2 will run as long as the button is held in. The device permits discharging of the dough by action of the agitator 1 with the bowl 6 in tilted position.

The clocks I21 and I21a are graduated in minutes, permitting observance for setting them for any desired duration of agitator operation. The low speed clock I21 will run its duration and automatically change from low to high speed of the agitator motors. Then the high speed clock, after keeping the agitator motors I2 running at high speed for its set duration, automatically stops the motors.

The control I24 for the conveyor and sifter motor I I2 and the control I32 for the blower motor I00 are fitted with a jumper line I39 to start these two motors simultaneously from either switch I24a or I32; but the blower motor I00 continues to operate, after the conveyor and sitter motor II2 has been stopped by the scalecontrolled switch I24, until the stop button of the blower motor control switch I32 has been pressed.

In addition to the start and stop switch I33 for the compressor motor 64, a pressure switch I40 is provided, with its pressure device interposed in the compressor discharge pipe and the switch in circuit with the start and stop buttons of the switch I33, for automatic starting at minimum pressure and automatic stopping at maximum pressure, respectively. It will be understood that this automatic pressure switch, as is well known in the art, may be adjusted to maintain a refrigeration effect within close limits, for the bowl 6, for the water supply and for the air supply that carries the flour or the like to the bowl.

It will be seen that I have provided, in a compact unit, a complete plant for combining dough ingredients and mixing and treating the dough, with complete control of all factors entering into the operation, automatically in those instances where automatic control is most necessary, and manually in place of the automatic controls if desired, and manually only, in those instances where manual control is adequate. This compact and relatively simple assemblage, arranged for convenient observation and control by the operator, permits of exact results in the preparation of dough. The ease of change in adjustments of automatic devices, and ready manual control, affords every modification of action of the apparatus to conform with different requirements, in working different materials for different products, with a minimum of thought and care. Chance of mistakes is reduced, and uniformity and excellence of product are better insured, by the eifective arrangement and correlation of devices.

It will be understood that not all of the devices are necessarily provided as herein set forth. For instance, the return of air through conduit 93 may be dispensed with, continually refrigerating a fresh supply of air from the atmosphere. One or more of the accessories, such as the light apparatus or the automatic yeast supply, may be omitted. The inspection lid I1 may be replaced by a continuation of the cover I3, stationary, with the bowl shaped accordingly. The automatic control of bowl tilting and the safety provision as to agitator operation and bowl tilting may be dispensed with. Any one or several of these changes may occur; and any of the devices may be modified, of themselves or in certain relations to each other. These or other modifications may occur in practice without departing from the spirit of my invention, and although I have rather specifically illustrated and described a certain preferred embodiment of my invention, it will be understood that I am not limited to such precise disclosure, but what I claim as new and desire to secure by Letters Patent is:

1. In mixing apparatus, a bowl mounted for tilting, mixing means in the bowl, a stationed cover for the bowl, closing the bowl when the bowl is tilted into position for mixing operation, water distributing means mounted on the stationed cover for discharge into the bowl, means stationed aside from the bowl and cover, for supply of water to said distributing means, a device mounted on the stationed cover for supplying a leavening ingredient to the contents of the bowl, and means for diverting a part of the water from said supply means to said device, introducing the water to said device with a disseminating action on the leavening ingredient therein.

2. In mixing apparatus, a tiltable bowl, mixing means in the bowl, a reversible motor operatively connected to said bowl for tilting it in one dimotion or another, means for reversing the operation of the motor, and means actuated by the tilting of the bowl to operate the reversing means in respective final stages of bowl tilting, whereby the extent of tilting of the bowl is automatically controlled.

3. In mixing apparatus, a tiltable bowl, operatable mixing means in the bowl,power means for tilting the bowl, power means for operating the mixing means, and control devices for energizing the respective power means, and having a mutually inhibitive relation to each other whereby operation of the mixing means is prevented while the bowl is tilted from position for operation of the mixing means, and tilting of the bowl from said position is prevented while the mixing means is being operated, and means for manually eliminating the mutually inhibiting relation of said control devices, whereby the mixing means may be operated by its power operating means while the bowl is tilted away from said position.

4. In mixing apparatus, a tiltable bowl, operatable mixing means in the bowl, power means operatively connected to said bowl for tilting it, reversible for tilting the bowl in one direction or another, means for reversing the operation of the power means, means actuated incident to tilting of the bowl, operating the reversing means in respective final stages of bowl tilting, whereby the extent of tilting of the bowl is automatically controlled, power means for operating the mixing means, control devices, respectively for the bowl tilting power means and the power means that operates the mixing means, having a mutually inhibitive relation whereby opertion of the mixing means is prevented while the bowl is tilted from position for operation of the mixing means, and tilting of the bowl is prevented while the mixing means is being operated, means operatable manually for starting and stopping tilting of the bowl independently of the automatic control of said tilting, and means for manually eliminating the mutually inhibiting relation of said control devices, whereby the mixing means may be operated by its power means while the bowl is tilted away from said position for operation of the mixing means.

5. In mixing apparatus, a bowl, an agitator in said bowl, power means for driving said agitator, operatable at a plurality of different speeds, time controlled devices for determining the duration of operation of the agitator-driving power means at the respective speeds, and means whereby a change from one speed to the other is automatically effected by the operation of one time controlled device at the end of a stage of operation determined by it, and the control of duration oi operation at the newly established speed is transferred to another one of the time controlled devices.

EDWARD J. LAU'IERBUR. 

